Timepiece



De- 9, 1969 y TosHlHlKo ooKl *l 3,482,392

TIMEPIEE Filed June 19, 1968 United States Patent() 3,482,392 TIMEPIECE Toshihiko Ooki, Suwa-shi, Japan, assignor to Kabushiki Kaisha Suwa Seikosha, Tokyo, Japan Filed .lune 19, 1968, Ser. No. 738,247 Claims priority, application Japan, July 1, 1967, 42/S6,223 Int. Cl. G04b I9/24 U.S. Cl. 58-126 5 Claims ABSTRACT OF THE DISCLOSURE A retaining member removably mounted on the longitudinally extending hub of an hour wheel to limit the longitudinal displacement along said hub of a rotatable member disposed for operative rotation about and relative to said hour wheel hub without interfering with said operative rotation.

Background of the invention The present invention relates to means for retaining a member operatively rotatable relative to the hub of an hour wheel about an axis dened by said hub, such as a day disk in a calendar watch or an unlocking wheel in an alarm watch.

In the known arrangements, a guard fixed on the plate of the timepiece or a washer mounted in the central opening of the timepiece dial have been used as a retaining means for such rotatable members. However, the provision of a guard on the plate necessitates additional parts, additional assembly processes and an increase in the thickness of the watch. Where a dial washer is used, it is ditiicult to keep the clearance between the dial and the rotatable member, e.g., a day disk, constant as the dial is fixed to the plate by its periphery and the central region thereof frequently fails to assume the desired position relative to said rotatable member. An excess of clearance causes the day disk or other rotatable member to disengage from the parts with which it engages. I-f, to avoid this defect, the thickness of said day disk is increased, whereby the depth of meshing is increased, the thickness of the watch will inevitably increase. When the dial washer is used it is extremely diflicult to measure the amount of longitudinal displacement along the hour wheel hub of the day disk permitted by said dial Washer. Where the central region of said dial sags towards said day disk or other rotating member, the existence of the dial washer increases rotational resistance of said day disk. This invention seeks to eliminate the above defects.

Summary of the invention Generally speaking, in accordance with the invention, retaining means removably mounted on an hour wheel hAub for limiting the longitudinal displacement along said hub of a rotatable member disposed for operative rotation about and relative to said hour wheel hub, is provided. Said retaining means may be formed as a continuous ring, a ring with a portion broken away to permit the spreading thereof, or in a U-shape. The removably mounted retaining means may frictionally engage the hub or ride in a slot formed therein.

Accordingly, it is an object of this invention to provide means for retaining a rotatable member disposed for perative rotation about and relative to an hour wheel hub without interfering with said operative rotation.

Another object of the invention is to provide such a retaining means which is removably mounted on said hub to permit easy assembly and maintenance of a timepiece.

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Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims. l

Brief description of the drawings For a fuller understanding of the invention, reference is had to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a sectional view of a portion of a timepiece incorporating a first embodiment of the arrangement according to the invention;

FIG. 2 is a sectional view of a portion of a timepiece incorporating a second embodiment of the arrangement according to the invention;

FIG. 3 is a sectional view of a timepiece incorporating a third embodiment of the arrangement according to the invention;

FIG. 4 is a first embodiment of the retaining means according to the invention;

FIG. 5 is a second embodiment of the retaining means according to the invention; and

FIG. 6 is a third embodiment of the retaining means according to the invention.

Description of the preferred embodiments Referring now particularly to the first embodiment of of the invention shown, in FIG. 1, hour wheel 1 is rotatable about its central axis and is formed with a hub portion extending longitudinally along said axis. Day disk 2 (or other rotatable member) is formed with a central aperture through which said hub extends and is disposed for operative rotation relative to said hub about said hour wheel hub axis. Ring-shaped retaining member 3 is removably mounted on the hub of hour wheel 1 and serves as a guard lfor the day disk 2 to limit the displacement of said day disk longitudinally along said hub.

As can be seen from the above the present invention provides a simplified construction composed of a minimum number of parts and provides an easy assembly process, which lowers the cost of manufacture of the time piece. This result is achieved by means of the ring removably fitted on the hour wheel 1 to serve as a guard for rotating member 2. This permits a reduction in the clearance between the day disk 2 and the ring 3, and therefore the production of a thin watch, since the day disk 2 can be made as thin as possible.

In another embodiment of the invention of FIG. 2, the ring 3 is seated in the groove provided on the hour wheel 1. In the embodiment of FIG. 3, the hour wheel is pro vided with taper for engagement with the ring 3. Retaining member 3 may be provided in a variety of shapes, such as are shown in FIGS. 4, 5 and 6. The retaining member according to the invention is not limited to these embodiments but a retaining member of any similar shape may be used freely. It is also possible to chamfer the outer end of the ring to facilitate the removal and insertion of ring 3.

What is claimed is:

1. In a time piece having an hour wheel rotatable about its axis, said hour wheel having a hub portion extending longitudinally along said axis and a rotatable member formed with a central aperture through which said hour wheel hub extends, said member being operatively rotatable relative to said hub about an axis defined by said hub, the improvement which comprises means 3 removably mounted on said hub to limit the displacement of said rotatable member longitudinally along said hub without interfering with the operative rotation thereof.

2. A timepiece as recited in claim 1, wherein said timepiece is a calendar watch, said rotatable member being the day disk thereof.

3. A timepiece as recited in claim 1, wherein said timepiece is an alarm watch, said rotatable member being the unlocking wheel thereof.

4. A timepiece as recited in claim 1, wherein said retaining means includes a substantially ring-shaped retaining member adapted for removable frictional engagement with said hour wheel hub portion.

5. A timepiece as recited in claim 1, wherein said retaining means is a substantially C-shaped retaining member removably engaged about said hour wheel hub.

`4 References Cited UNITED STATES PATENTS 240,380 4/1881 Buck 58-126 267,824 11/1882 Bell 58-126 5 3,151,441 10/1964 Tsuzuki srs- 85.5

FOREIGN PATENTS 499,398 11/ 1950 Belgium. 318,497 1/ 1957 Switzerland. 10

RICHARD B. WILKINSON, Primary Examiner G. H. MILLER, JR., Assistant Examiner 15 U.S. C1. X.R. 

